Charles s



Oct. 2 1923.

C. 5. BUSHNELL.

AUTOMATIC TRAIN CONTROL SYSTEM Original Filed Dec. 16. 1916 Mimi M wit. 2, i923.

UNITED STATES PATENT OFFICE.

CHARLES S. BUSHNELL, OF SYDNEY, NEW SOUTH WALES, AUSTRALIA, ASSIGNOR 'IO GENERAL RAILWAY SIGNAL COMPANY, OF GATES, NEXV YOBK;A CORPORATION OF 1? EV? YORK.

Application filed DecemberilG, 1916, Serial No. 137,409. Renewed March 8, 1923.

. Bosn- .f on oil the United States. and a of the city of Sydney, State of Flew outh ales, Commonwcalth oi Australia. havi invented a new and useful Autolrain-Co itrol System, of which the following is a specification.

This invention relates to automatic train.

control ystems, more particularly to the impulse devices and traelrway circuits neces sary for the proper control of the train.

in one type" of automatic train control sys cm, to which thisinvcntion more partitularl'y relates, the apparatus on the train which controls the mo ment thereof is set into operation when it is desired to control the ain and continues in operation until v the desired control has been acconuglislied,

pied.

whereupon this apparatus. reset or. re stored to its initial or normal condition ready for the next operation. in other 'ds, train control systems of tliistype' may he said to have a cycle oi operation, which initiated at the point atfwhich it is desired to commence a reduction in speed and the next block in-advance is occupied and before the train has traveled through the lenc'iih of the t clock, the train iornerly in the block in advance has left that block so that it is proper to restore the apparatus on the first train to its initial condition.

Viith these considerations in view the primary object of this invention is an arrangems t and construction of parts in an automa ic train control system such th at the cyrle of operation of the apparatus on a train following its initiation at the entrance to a block may be terminated at intermediatepoints in the block.

Other objects and advantages will appear as the description of the invention proand the novel features of invenwherein like character-sot reference designate corresponding parts throughout the several views, and in which:

Fig. 1 18 a diagrammatic view showing a si .iplified construction of a train control apparatus to which this invention is appli cable, together with the construction and arrangement of parts embodying this invention; and Fig. 2 is a diagrammatic View of a portion ofa railroad track and illustrates an arrangement of trackway circuits suitable for controlling the train control apparatus shown in Fig. 1.

Referring" to the accompanying drawing, numeral 1 designates a portion of a track rail of the ordinary railroad track upon which the Wheels of the vehicle or train travel; and for simplicity the vehicle or train is shown as comprising one wheel 2 and an axle 8. According to the embodiment or" the invention illustrated communication between the track and the vehicle used for the proper control of the train control apparatus onthe vehicle is obtained by the mechanical and electrical cooperation of a Contact shoe carried by the vehicle with suitable ramps or contact rails located along the track. These contact shoes may be of any suitable construction, and for simplicare shown diagrammatically in the acs companying drawing as'comprising a'vertically movable plunger 5 slidabl mounted in a bracket 4t carried by the vehicle in any suitable manner and for simplicity assumed to be made of wood or other suitable insulating material. The shoe or plunger 5 is provided with-a suitable foot or enlarge.

ment at its lower end constituting the portic-n thereof which engages the ramps; and said plunger is pressed. downward to its lower osition, shownin Fig. 1, by means of a compression spring 7 interposed between the bracket 1 and a collar 6 fixed to said plunger. Secured to the upper end of the plunger 5 is a button 8 of suitable insurng material which is larger than the stem portion of said plunger and which is adapted to forma stop for limiting the downward movement thereof; and this button 8 is arranged to lift a contact spring 9 secured to the bracket 4 out of electrical contact with a contact piece 10 on said bracket when the plunger 5 is raised.

In the simplified construction of the train control apparatus illustrated, a worm 11 is fixed to the axle 3 and meshing with said worm is a worm gear 12 secured to the lower end of a shaft 18 which is revolubly mounted in suitable supports 14 and is held against endwise movement in said supports by suitable collars l5 pinned to said shaft. Secured to theshaft 13, as by means of a pin 16, is a collar or block 17; and slidably mounted on the shaft below the block 17 is another block 18. Pivotally connected to the block 17' are links :9 which are also pivotally connected to n i h l balls 93 7-; and similarly connecting tans -50 with the block compression 18 are other links n. in spring 21 is interposed between the two blocks 17' and 18. The construction descri will. be readily recognized as that of a con eational speed responsive device similar to that of the well known centrifugal, governor, and

the operation of this speed responsive device will be apparent without further expl-anation. Journaled on a fixed stud 22 is an angle lever L, one arm 28 of which extends. to the speed responsive device above described and is formed with bifurcations 24 carrying rollers 25 engaging with flanges 26 secured to the block ,18, so that as the block 18 moves up and down in response to changes in the speed ofrotation of the shaft 18', the arm 23 of the angle lever L s correspondingly moved up and down.

construction illustrated a beveled gear 27 is fixed to the shaft 13 and meshes with a similar beveled gear 28 secured to a shaft 29 which is journaled in supports 30 and is held against endwise movement in said supports by suitable collars 31 fastened to' said shaft. Fixed to theshaft 29 is a worm 39' which meshes with a worm gear 33 mounted on a fixed bearing stud or pin 34. A smaller gear 35 is connected to the gear 83 so as tov turn therewith, and this smaller gear meshes with a larger gear 36 journaled on a bearing stud 37. In a similar way intermeshing gears 38, 89, 40 and 41 are j'ournaled on hearing studs 43 and 44, and serve to complete a train of gears which will be recognized as the well known reduction gearing. Pivotally mounted at one end on the bearing stud 44 is a lever 45 which carries two intermeshing gears 46 and 47, the gear 46 being also in mesh with a gear 42 connected to the gear 41.

Disposed above the outer or free end ofthe lever 45 is an electromagnet, herein termed the cam control magnet K, which comprises two coils 48, the pole pieces of which are connected at their lower ends by the usual yoke 49, said yoke being fastened to suitable'fixed lugs or supports. The armature 50 of the cam control magnet K is guided by pins 51 secured in the pole pieces of the coils 48, and tl'iisarmature 50 is rigidly connected to a rod 52 which extends downward through a guiding opening in the yoke 49 and which is pivotally connected to the outer end of the lever 45. A collar 53 is fixed to the rod 52, as by means of a pin, and interposed between said collar and the yoke 49 is a compression coil spring 54 which tends to move the rod and lever 45 to their upper position. i

Disposed above the lever 45 and the gears 47 and 46 carried thereby is a cam shaft 55 supported in suitable bearings (not shown), and fixed to this cam shaft55 is a gear 56 which is arranged in the same plane as the gear 47, so that when the lever 45 is in its upper position, opposite to the position shown in Fig. 1, the gear .47 may mesh with the gear 56., Suitable means is provided for returning the cam shaft 55 to its initial position, and in the simplified construction illustrated this result is accomplished by a counterweight 57 fastened to the gear 56, so that when the cam shaft 55 is free to turn it is moved to the position shown in Fig. 1 by the counterweight 57 which tends to assume a position directly underneath the shaft 55. Fixed to the cam shaft 55 is a cam-shaped plate, herein termed the cam 58. The factors determining the shape of this cam 58 will be explained. hereinafter. Also rigidly secured to the can: shaft 55 is another plate 59 the periphery'of which is formed with two concentric por--- tions, of different radius, whereby shoulders 60 are formed in the periphery of said plate for the purpose more fully explained hereinafter.

The arm 61 of the angle lever L extends to a point below the cam shaft and pivotally connected to the lower end of a floating lever (32 which carries at its upper end a roller 63 bearing against the of the cam 58. A link 64 is pivotally connected at one end to the middle point of the floating lever 62 and at its other end to an arm 65 secured to a contact sector 6.6 which is revolubly mounted on a fixed pin or stud 67; The outer edge of the contact sector 66 is formed with a shoulder 68 for the purpose hereinafter explained. Arranged adjacent. to the contact sector 66 is a suitable fixed support 69 which carries contact supporting blocks 70 of insulating material; and anchored at one end to the support 69 is a tension spring 71, which is connected at its other end to the arm 65. Fastened to the 6 contact supporting blocks 70 and the support 69 are a number of contact; supports 72 which support contact lingers 73, 74, 75 and T6 and which also serve as binding posts for establishing electrical connection to said contact fingers.

Each of these contact fingers is'mounted on its corresponding support 72 in the'same manner and a description of one will sutlice for all. Refer .ng to the contact finger 76, this linger is i. rmcd at its lower end with a pair-of ears 77 which are connected by a hori'routai pin 78 to the corresponding con tact support 72, this construction serving, to support the contact finger 76 so that it may be rocked in a vertical plane. The contac'. finoer '76 is pressed 111 one direction,

secured to the contact support 72 in any.

suitable i'nanner.

Secured to the lefthand face of the con tact finger T3 is a freely revoluble roller 8O f insulating material which is arranged to bear against the edge of the contact sector Normally, when the parts are in the sition shown in Fly. 1, the contact finger moved some distance to the right from its contact support 72, and the cooperating t finger 7 is also moved a distance from its contact support, the distance between the contact finger 74 and its support, however, being less than the distance between the contact finger 73 and its support; and it is apparent that if the contact finger 73 were allowed to move to the left, the conact lingers 7 8 and 74 would separate since he contact finger 74 would move only a ort distancecompared with the distance li which the contact finger 73 would move. The contact fingers 7 5 and '76 are also normallv closed and will separate when the er 7 5 is permitted to move toviewed in Fig. 1. rock lever is pivotally mounted on A .c as the plate 59, and carried by said rock lever is a freely revoluble roller 83 which is pressed against the edge of said plate by a tension spring 84. To the upper end. of the rock lover 8: 3 is connected'a link 85 which is adjustably connected, as by of nuts 87, to another link 86 which ivotally connected to the upperend of the contact finger 'r' 5.

According to the embodiment of the invention illustrate it is contemplated that the speed of the vehicle will be retarded by known systen'iof air brakes; but tern of brakes is well known to pin 81 and arranged in the same.

made to show the construction and arrangement .of its parts in detail. As is well known, this system of airbrakes includes a train pipe 88 and the venting of this train pipe causes an application of the brakes. In order that the train control apparatus may automatically cause such an application of the brakes a suitable valve 89 is connected to the train pipe 88 and is arranged to be operated by a solenoid 90, the arrangement preferably employed and illustrated in Fig. 1 being that in which the valve 89 is closed when the, solenoid 90 is energized and is automatically opened by a spring or other meanswhen said solenoid is deencrgized.

The speed control apparatus is governed electrically by a relay SC on the vehicle and hereinafter termed the speed control relay; and this speed control relay SC is pro vided with two armatures or contact fingers 91 and 92, whichare illustrated convention ally. The speed control relay SC is in turn controlled by another relay P carried on the 'ehicle, and hereinafter termed the pick-up relay; and this pick-up relay P is provided with one armature or contact finger 93.

In Fig. 2 there is shown a stretch of track, over which traflic normally moves from left to right, in the direction indicated by the arrow T; and the track rail 1 of this stretch of tradl: is divided by insulating joints 9% in the usual manner into blocks, as the blocks 1,413. and C, the entire length of only the the block Bbeing shown. In the particular embodiment f the invention illustrated, the trackway circuits are supplied with alternating current derived from a suitable source as a generator 95, which is connected to line wires 96 and 97 extending throughout the length of the railroad. The parts and electrical conductors associated with each block are substantially the same, and these parts and conductors are for convenience given corresponding reference characters with distinguishing exponents added thereto. Adjacent to one end of each block, preferably the exitend thereof, is located a track transformer 98, the primary of which is: connected across the line wires 96 and 97, and the secondary of which is connected across the track rails 1 and l of the corresponding block, At the other end of each block a track relay 99 is connected across the track rails, this relay being of suitable construction so as to be responsive to alternating ourrent and being provided with two contact cated adjacent to the entrance end thereof is a contact rail or ramp R- which is of suitable construction and is supported in any suitable manner on the ties supporting the track rails, but so as to be insulated from said track rails. The different ramps R are disposed in such a position with reference to the track railsthat they will be engaged by the contact shoe on a passing vehicle. Between the ends of some or all of the blocks are located other ramps RI of similar coin. struction, herein termed intermediate releasing ramps, there being any number of these intermediate releasing ramps at any desired distances apart located along the first and greater part of each block for the purpose iii) of track of certain particular physical char acteristics. In general it may be said that the shape of the cam 58 is selected so that when said cam is gradually turned by the progress of the vehicle it causes the roller to assume different positions in accordance with a predetermined decrease in the permissive speed for the vehicle, in order that the position of the roller 63 at any point in the travel of the train following theini'tial operationof the cam 58may correspond to the permissive speed at that point which the vehicle should not eXceed if it is to be brought to a stop or to a predetermined low speed by an application of its brakes before reaching a certain point in advance, generally the entrance end of the next block. In the particular kind of cam illustrated, the lengths of the radii of said cam correspond to speed and the angular displacementof said earn from its initial position, shown in.

- Fig. 1, corresponds to distance traveled by has been made to show this cam precisely correct in shape. Furthermore, as indicated hereinbefore, the shape of the cam 58 is determined with reference to a certain stretch of track, having certain grades, curves, or other factors characteristic of this stretch of track which affects the retarding effect of the brakes on a vehicle; and, as is well known by those skilled in the art, in practice the different stretches of track or blocks of a railroad will not be necessarily of the same length, nor of the same grade, nor will the other physical characteristics, such as curves be the same, so that if it is desired to control the speed of a vehicle in these several blocks having different physical charact'eristics precisely in accordance with the .nal or initial position, the speed control e ay is energized by a circuit which y be traced as follows: commencing at battery 103, conductor relay SC, conposition, which may be termed the doctors and 106, armature 91 in its upper position, conductor 107, contact spring 9, contact piece 10, and conductors 108 and conductor 1.0 1, relay SC, conductors 105and 110', armature of the relay I" in its upper position, and conductors 111 and 109 back to the battery 103. One terminal of the winding of the relayPis connected by conductor 112 to the frame or axle of the vehicle, so that this conductor is electrically connected to the track rails, and the other terminal of the winding of the relay 1 is connected by a conductor 113, preventive resistance 11 1, and conductor 115 to the contact shoe 5. There is a low resistance shunt for the preventive resistance 114 comprising conductors 116 and 117 which is closed by the con tact fingers 75 and 76 when the parts of the train control apparatus are in the normal condition as shown in Fig. 1.

When the speed control relay SC is energized and its armature 9:2 is in its upper po sition, the cam control magnet K is energized by a circuit which may be traced as follows: commencing at the battery 118, conii issuine that a vehicle, equipped with the train control apparatus as shown in Fig. 1

and having that apparatus in its normal or A and initial condition, is in the block about to enter the block B; and further as led by another train. Since the i not occupied, the track relay 99 so that a partial circuit estabiil'erence of potential. equivalent to age of the entire secondary of the ransforiner 102 is established between the ramp 5' and a track rail, said partial circuit being traced as follows: commencing at the ramp ll, conductor 126, armature 100' in its upper position, conductor 127, secondary of the tansforn'ier 102, and conductor 128 to the track rail 1. hen the vehicle in queslien proceeds to the point where its contact shoe 5 engages the ramp B, said contact shoe is lifted by the mechanical cooperation of said and said ramp and is also electrically connected to said ramp. The lifting of the contact shoe '5 interrupts the normall closed circuit hereinbefore traced for enei sing the speed control relay SC; but under the tra tlic conditions assumed the pick-up relay P is energized by a circuit which inay be traced as follows: commenc ing at thoramp R, conductor 126, arma ture 100 in its upper position, conductor 127, secondary the transformer 102, conductor lo the track rail 1, through the wheels an .xles of the vehicle, along conductcr112 to the relay P, thence along conductors 113 and 11. contact fingers 76 and 75, conductors 1116 and 115 to the contact shoe 5 and back tothe ramp R. The pick-up relay P leing energized maintains the speed control relay SC energized by closing the circuit therefor controlled by its armature 93. As the vehicle in question progresses and the first pair of wheels and axle thereof enter the block, the track relay 99 is shunted and its armature 1 drops thereby interrupting the partial uit associated with the ramp R, but since the block C is not occupied there established anotherpartial circuit which supplies current to the pick-up relay P and "ains it energized, this last mentioned .1 il circuit being traced as follows: commencing at the ramp R, conductor 126, ar- *niture 100 i lower position, conductors Q and 13 i), -armature 101 in its upper posiiion, conductor 131 to an intermediate tap of the secondary of the transformer 102 and conductor 128 to the track rail 1. It can be seen that the dif'ference of potential established between the ramp R and the track rail 1 by the last traced partial circuit less than that established by the first traced partial circuit associated with said ramp. The pick-up relay l is so constructed that when the preventive resistance 11 1 is included in its circuit the higher difference of potential above mentioned will cause sufficient current to flow through said relay to raise its armature 93, but the low difference of potential will not cause suilicient current to How through said relay to raise its armature. \Vhen the preventive resistance 114 is shunted, however, the low difference of potential is sufficient to cause the relay P to raise its armature 93. Under the particular conditions assumed the preventive resistance 11 1 is shunted so that the low difference of potential established between the ramp R and the track rail 1 after the first pair of wheels and axle of the vehicle under consideration have entered the block B is sufficieiit to maintain said relay P energized, and in turn keep the speed control relay SC energized. Consequently under the tral'lic conditions assumed, that is, when neither the block B nor the book C is occupied, the vehicle may enter the block 13 without having the normal condition of its speed control apparatus changed.

F or the next condition of tralfic to be considered assume that the vehicle in question is in the block A and about to enter the block B, and that while the block B is not occupied by another train, another train does occupy the block C. The same operation of parts occurs before the first pair of wheels and axle of the vehicle in question enter the block 13 as has been previously described; but after the vehicle has entered the block B and the armature 100 of the track relay 99 has dropped, there does not exist any difference of potential between the ramp R and the track rail 1 by reason of the fact that a train is assumed to occupy the block C so that the armature 101 of the track relay 99 is in its lower position. Consequently, the armature 93 of the pick-up relay P drops because current is no longer supplied. to said pick-up relay 1, and since the contact shoe still in engagement with the ramp R, all supply of current to the speed control relay S is cut oil, and hence the armatures of said relay SC drop. Tie dropping of the armature 91 of the speed control relay SC opens another break in the normally closed circuit for energizing said relay, so that after the contact shoe 5 has left engagement with the ramp R he contact spring 9 has again made e contact with the contact piece 10, nevertheless the normally closed circuit for energizing said relay SC remains traveled by the vehicle, so that the upper. end

of the floating lever 62 assumes different positions more and more to the left of that shown in Fig. 1 the permissive speed of the vehicle desired decreases. The lower end of the floating lever 62 is connected to the arm'Gi of the angle lever L and is caused to assume different positions more and more to the letter that shown Fig. 1 according to the actual speed or the vehicle as measured by the speed responsive device. If it happens, and this usually the case under ordinary circumstances, that the ve-- hicle as it passes the ramp lltraveling at a comparatively high rate of speed, the lower end of the floating lever 62 w be in a position to the left of the p ion shown in Fig. 1 such that the contact secto" 66 'w-ill be rocked downward until the shoulder 68 is only a short distance above the roller 00. As the vehicle oro 'resses and 1 V V ,1 e

the cam 08 causes a movement of the upper end of the floating lever 62 more and more to thele'l't, it can be seen that the lower end of said floating lever must be moved a correspondingextent to the right in order to prevent further movement of the link 64 to the left, as it is viewed in Fig. 1, and a consequent further movement of theconta ct sector 66 until the shoulder 68 is brought opposite to the roller 30. the contact sector 66 is moved l ar enough to bring the roller 80 opposite the shoulder 68, the contact lingers 73 and 7st are allowed to separate and cause an auton'iatic application of the l '"alres. In otherwords, the actual speed of the vehicle which. causes the lower end of the floating, lever 62 to assume different positions must decrease at the same rate and inthe same manner as the permissive speed for the vehicle, determined by the position given to the upper end of the floating lever 62 by the cam 58, decreases, in order that an automatic application of the brakes will not result. From this it can be seen that as the vehicle progresses through the block B it is compelled to reduce its speed in accordance with'the desired curve of permissive speed,

so that if the movement of the cam 58 continues, the vehicle would be brought to a stop or to a predetermined low speed by the time it reached the end of the block B. i

As the vehicle progresses through he block l3 and the cam shaft 55 is gradually turned in accordance with the distance traveled, the plate 59 is also gradually turned, and after the train has progressed for a certain distance, as for example, for 75 or J61 cent of the length of the block 13, said plate 59 has been turned far enough so that termed a run-down or distance measuring 7 device, measures of]? the distance traveled by the vehicle into a block and conditions the control of the cam 58 accordingly. In this way, after the vehicle has traveled a prede termined part of the length of the block B into that block, the shunt around the preventive resistance 11% is broken, so that at any point in the remaining part of the block 13 only a ramp, between which and a track rail a high difiference of potential exists, is capable of energizing the pick-up relay P.

' Suppose that during the'time'the vehicle is reducing its speed and traveling through the block B, the train assumed to be in the block 0 remains in that block; then, when the vehicle in question reaches the ramp R at the entrance to the block 0, either a low diflerence of potential or no difi erenceojt potential will exist between this ramp and the track rail 1, by reason of the fact that the armature of the track relay 99 is in its lower position and is connected to the conductor 129 leading to the track relay of the block (not shown) next in advance of the block C, so that if this block next in advance is not occupied a low'difl'erence of potential is established, whi-leif this next block in advance is occupied no difference of potential is established. In either case the pick-up relay F is not energized, since the preventive resistance 11 1 is in series therewith. Suppose, however, that by the time the vehicle in question reaches the end of the block B, the train formerly occupying the block C has moved out of that block. Then, under these conditions, a high difference of potcntial exists between the ramp R and the track rail 1 so that, regardless of the fact that the preventive resistance 114 is included in series with the pick-up relay P, this pickup relay P is energized, the speed control relay SC in turn is energized, and finally the cam control magnet K. The energization of the cam control magnet K moves the lever to its lower position and disengagcs the gear d7 from the gear 56, whereupon the cam shaft 55 and its associated parts are returned ill for the next operation. The next operation may be caused to occur when the vehicle enters the block C, providing the next block in advance of the block C is occupied, in the same manner and for the same reasonlas hereinbefore explained in connection with the entrance of the vehicle into the block B when another train occupies the block C.

In order to avoid delaying a following vehicle or train,'it should be possible for the train control apparatus on said following vehicle to be released or restored to its initial condition after its operation has once been initiated, as soon as the train which occupied the next block in advance and which was the cause of the initiation of the operation of the train control apparatus, has

moved out of that next block in advance.

1 release and restoration of the parts of the train control apparatus on the following ve hicle to its initial condition at an intermediate point in a block.

As pointed out hereinbefore, the preventive resistance 114 is shunted during the movement of the vehicle through the first and greater part of the block B, and it can be seen that at any point in this first part of the block a medium diiference of potential between a ramp and a track rail is suflicient to energize the pick-up relay P and cause a restoration of the parts of the train control apparatus to the initial or normal condition. Consequently, in order to obtain a release at an intermediate point in a block, as tl e block B, it is only necessary to place at the different points desired an intermediate releasing ramp, such as the ramp. RI, which is connected by a conductor 132 to the conductor 130. When the vehicle first enters the block B, there being another train in the block C, the intermediate releasing ramps RI do not have any difference of potential established. between them, and a track rail by reason of the fact that the armature 101 of the track relay 99 is in its lower position; but it can be seen that as soon as the train leaves the block C and the armature 101 returns to its upper position, a medium difference of potential is established between each and all of one or more intermediate releasing ramps RI in the block B, so that as soon as the vehicle in the bloclr B passes one of these intermediate releasing ramps BI the train control apparatus is restored to its normal condition, permitting the vehicle to proceed to the end. of the block B without unnecessary delay. If a vehicle should enter the block B when that block is occupied by another train, the intermediate releasing ramps RI would not: cause a restoration of the parts of the train control apparatus on that vehicle to the initial or normal condition, even if the block 0 were not occupied at the'time and a low difference of potential existed between said intermediate releasing ramps and a track rail, because when the first vehicle entered the block B, the preventive resistance would be included in the circuit for the pick-up relay P, thereby making the low difference of potential insufiicient to raise the armature 93 of said relay P. The preventive resistance 114 would not be shunted under the conditions just assumed when the vehicle entered the block B because the cam shaft 55 would have been turned through an angle equivalent to the length of the block A while the vehicle in question was passing through the block A.

Although I have particularly described the construction of one physical embodiment of my invention, and explained the operation and principle thereof; nevertheless, I desire to have it understood that the form selected is merely illustrative, but does not exhaust the possible physical embodiments of the idea of means underlying my invention. 1

What I claimv as new and desire to secure by Letters Patent of the United States, is:

1. In an automatic train control system, i

in combination: a vehicle and a track therefor divided into track circuit blocks; train control apparatus carried by the vehicle and operating to cause a continuing reduction in speed of the vehicle following its initial operation; a ramp at the entrance to each block; a partial circuit associated with each ramp and controlled by the track circuit of the corresponding block for establishing a difference of potential of a predetermined value between said ramp; and said track rail when that corresponding block is not occupied; a second partial circuit associated with each of said ramps and controlled by the track circuit of the next block in advance of the corresponding block for establishing a difference of potential of a predetermined value less than the value established by said first mentioned partial circuit when said next block in advance is not occupied; a relay on the vehicle for governing said train control apparatus; a partial circuit on the vehicle including said relay; means for connectingsaid partial circuit on the vehicle with the partial circuit associated with each ramp as the vehicle passes the successive ramps; means on the vehicle for preventing said relay from responding to the difference 1 U ii iii] of potential established by said second mentioned partial circuit, said means being nor mally ineffective and being rendered ellective alter the. vehicle has traveled a predetermined part of the length of the corresponding block; and other ramps located between the ends of each block and connected to said second mentioned partial circuit corresponding to that block.

2. In an automatic train control system, in combination: a vehicle; train control apparatus carried by the vehicle; a relay for controlling said app circuit for said relay; a preventive resistance inserted in said circuit; a normally closed shunt for said resistance; and'means governed "by the distance traveled by the vehicle for interruptin said shunt.

In :an automatic train control system,

in combination: a vehicle; automatic train control apparatus carried by the vehicle; an electrically operable device for governing said apparatus; and means controlled by the distance traveled by the vehicle for changing the operating characteristics of said means 'toprevent its response to the impulse of said character afterthe vehicle has traveled a part of said predetermined distance; and 'tra ilic controlled impulse devices along the tracl for governing said first mentioned means.

' In an automatic train control system, in combination: a'vehicl'e and a track therefor divided in'to'blocks; automatic train control apparatus on the vehicle having an ini'tial'condi tron and an ultimate condition and changing gradually from its initial condition to its ultimate condition during the movement of the vehicle over the length of a block; traliic controlled means associated with each block for governing said apparatus to initiate the operation thereof; and

other traiiic controlled means associated with each block for governlng said apparatus and effective to restore it toits initial condition prior to its reaching its ultimate condition but not thereafter.

6. In an automaticitrain control system, in combination: a vehicle and a track there for divided into blocks; automatic train control apparatus on the vehicle; and impulse devices located at the entrance to each block and at intervals in the first part of that block for controlling said apparatus,

aratus; a controlling said impulse devices located at intervals in the first part of a block being controlled by the next block in advance and being ca pable of cont-rollingsaid apparatus to restore it to its normal position providing; said next block in advance is not occupied and provided said block was not occupied when the vehicle entered it.

7. In an automatic train control system, the combination with a vehicle and a track tllQl'SrOI divided into blocks, of automatic train control apparatus on the vehicle adapted when set into operation to ,continuc in operationuntil restored, impulse transmitting (evices at intervals between the ends of'eachf block and capable of transmitting an impulse of a predetermined charactor to the passlng vehicle when the next said last mentioned distance controlled means. 1

8. In an automatic'train control system, the combination with a vehicle and a track therefor divided into blocks, of automatic train control apparatus on the vehicle adapted when set into operation to continue in operation until restored, impulse devices at intervals between the ends of each block and energized when the next block in advance is not occupied control means on the vehicle normally responsive to the energized condition of said impulse devices and adapted to restore said train control apparatus, and means acting after the vehicle has traveled a predetermined distance follovw ing the initiation of the operation of said apparatus for preventing said control means from res onding to the energized conditionott said impulse devices.

9. In an automatic train control system.

the combination with a vehicle and a track therefor "divided into blocks, of automatic tram control apparatus on the vehicle capable of imposing decreasing restrictions on the speed of the vehicle during its progress through a bloel'z, impulse transmitting means at the entrance to each block capable of transmitting to the passing vehicle. an impulse of a predetermined character when the corresponding block is not occu pied, other impulse transmitting means at intervals between the ends of each block and adapted to transmit an. impulse a anti'ally to the length of the block, and

different character when the block next in advance is not occupied, control means on the vehicle for restoring said train control apparatus to a higher speed condition, means governed in accordance with the progress of the vehicle and setinto operation and restored in correspondence with said train control apparatus for changing said control means when the vehicle has traveled substantially, the length of the block, said control means when unchanged being responsive to the impulses of both characters, but when changed only to the impulse of the predetermined character transmitted by the first mentioned impulse transmitting means, whereby the train con trol apparatus on a vehicle may be restored to its initial condition at intermediate points in a block when trafiic conditions in the block next in advance become safe but cannot be restored at such intermediate points behind another vehicle occupying the same block. I

10. In an automatic train control system, the combination with a vehicle and a track therefor divided into blocks, of automatic train control apparatus on the vehicle adapted when set into operation to impose decreasing limitations on the speed of the vehicle during its progress through a block and to continue in action until restored, means associated with each block for setting said apparatus into operation when the vehicle enters a caution block next in the rear of an occupied block, means associated with each block for restoring said apparatus at intermediate points in such caution block when traflic conditions in thenext block in advance become safe, and means governed in accordance with the progress of the vehicle for rendering said last mentioned means ineffective after the vehicle has traveled a distance corresponding substantially to the length of the block.

11. In an automatic train control system, the combination'with a vehicle and a track therefor divided into blocks, of automatic train control apparatus on the vehicle adapted when set into operation to limit the speed of the vehicle to a predetermined low speed after the vehicle has traveled through a block and to continue such limitation until restored, a control device for governing said apparatus, trackway impulse devices governed in accordance with traflic conditions for transmitting impulses of distinctive characters to the passing vehicle at different points in a block to influence said control device, and means governed in accordance with the progress of the vehicle for preventing said control device from being influenced by impulses of one character after the vehicle has traveled a predetermined distance,

. 2. an automatic train control system,

the combination with a vehicle and a track therefor divided into blocks, of automatic train control apparatus on the vehicle adapted when set into operation to continue in operation until restored, impulse transmitting means at the entrance to each block adapted to cause said apparatus to be restored or set into operation respectively in accordance with trailic conditions in the corresponding block and the next block in advance, other impulse transmitting means at intervals between the ends of each block and capable of transmitting a restoring impulse of a predetermined character to the vehicle when the next block in advance is not occupied, a control device on the vehicle normally responsive to said restoring impulses and effective to restore said apparatus, and means acting after the vehicle has traveled a distance bearing a predetermined relation to the length of the block through which the vehicle is then passing for preventing said control device from responding to said restoring impulses.

13. In an automatic train control system, the combination with a vehicle and a track therefor divided into blocks, of automatic train control apparatus on the vehicle, a control relay for governing said apparatus, impulse transmit-ting means at intervals between the ends of each block and normally effective to cause energization of said relay when the next block in advance is not occupied, and means governed in accordance with the progress of the vehicle for preventing such energization of the control relay after the vehicle has traveled a distance corresponding substantially with the length oi a block. 7

14. In an automatic train control system, in combination, a vehicle and a track therefor divided into blocks, an impulse device at the entrance to each block and adapted to transmit to the passing vehicle an impulse of one kind when the corresponding block is not occupied, other impulse devices at intervals in each block for transmitting another kind of impulse when the next block in advance is not occupied, automatic train control pparatus on the vehicle adapted when set into operation to change from an initial condition to an ultimate condition during the progress of the vehicle through a block,

a control device for governing said apparatus, and means governed by said apparatus for rendering said control device responsive to either kind of impulses when said apparatus is in it initial condition but only to the .first mentioned kind of impulses after said apparatus has attained its ultimate condition. 4

15. In an automatic train control system, the combination with a vehicle and a track therefor divided into blocks, of automatic train QQnt Ol apparatus on the veh cle adapt mally. capable of restoring said apparatus at intermediate points in a block whentrat lic' conditionsin' the next block iii advance become safaandmeans rendered active multancously', with the train control apparatus and governed in accordance with the.

progress ofjthevehicle for preventing said last mentioned means from, acting after the vehicle has traveled a distance corresponding substantially with the length of the block. 7 V I v 16; l'n an, automatic train control system, the combination with a vehicle and a track therefor divided into blocks, of automatic train control" apparatus on; the vehicle including a perm ssive speed device adapted when operatingto change to an ultimate.

conditionduring the progressot the vehicle through a block, a control device for rcstoring said permissive speed device to its ini- 30 tial' condition, impiilse transmitting means between tlleends of each block normally etfectivc' to; influence said control device when the next block 1n advance becomes unoccupied and means'for preventing the responseof said control device to the influence oi. said impulsetransmitting means after the pen missive speed; devlce has changedto a ire;

determinedextent: V

17. In an automatic train control system,

the combination with a vehicle and a track "therefor divided into blocks of automatic vehicle for changing the ODPOSitlOildO the" train control apparatus 011 the vehicle'in eluding an element adapted to change gradually from an initial condition to an ultimate condition, a control relay on the vehi cle :torgoverning said clement a circuit for encrgiZing said relay, means for api'ilying currents of different voltages 'toisaid circuit at points along the track, and means;- governed.inaccordancewith the progress of the 18. In an automatic train control system, the combination with a vehicle and a track therefor, of automatic train control appa rates including a permissive speed device adapted to be driven by the wheels of the vehicle, a control relay "for governing said permissive speed device, an element also geared to the wheels of the vehicle, a circuit controller operated by said element when the vehicle has traveled a distance corresponding to a change of the permissive speeddevice to a predetermined extent, and means attuned by sai clrcu t c n ro l lating the effective therefor divided into hlociic ilor controllii the cnergiaation oi? said con trol relay.

19. In an auton'iatictrain control system,

the combination with a vehicle o't autodistance traveled by the vehicle, means partly on the vehicle and partly along the track for controlling said element in accordance with tral'lic conditionsinadvance, and means etlective atter said element has changed to a predetermined extent for l ege 7 action of said first mentioned means.

Qllln an automatic train control system the combination witha vehicle and a traclr therefor divided into blocxs each provided with a track relay otan impulse device at the entrant-etc each block, a circuit for energizing said impulse device including: a front contact of the track relay ot the corresponding bloclr, a second circuit for energiaingr, said impulse device including: aback contact of the track rclayot thecorrcsponrh in combination, a track divided into blocks,

an impulse. device at the entrance to each block adapted to transmit impulses oil a oredcterinined character to a passing vehicle when the corresponding block is not occupied, and other impulse devices at intervals along each hlock'and adapted to transmit impulses of a different character to a passing vehicle whenthe next block in advance is not occupied; l

22. In an automatic train control system. the combination with a vehicle and a traclr therefor divided into blocks, of automatic train control apparatus on the vehicle a noi mally energized relay on the vehicle governsaid apparatus means for causing energization and deencrgrization ol said relay successively at the entrance to each block iii atwrm dance with traffic conditions in the corresponding; block and the next bloc]; .in adtrolled v Inan automatic train control sy tem, H

the combination with a i" rain control apparatus, for,

at the time the vehicle adapted when operating to impose decreasing limitations upon the speed of the vehicle as it progresses, and means including impulse devices and controlling circuits therefor adapted to set said apparatus into operation upon entrance of the vehicle into a block next in the rear of a block occupied by another vehicle, said means being also adapted to cause restoration of said train control apparatus at intermediate points in the block when the next block in advance becomes clear.

24:. In an automatic train control system, the combination with a vehicle, of automati train control apparatus there for comprisinga permissive speed device adapted to change in accordance with the progress of the vehicle alone; the track, a relay "for controlling said permissive speed device, a circuit for controlling the energization of said relay, and means actuated when said permissive speed device has changed to a predetermined extent for controlling said circuit.

25. In an automatic train control system, the combination with a vehicle and a track therefor divided into blocks, of automatictrain control apparatus therefor character- .ized by changing from an initial to an ultimate condition and by remaining in such ultimate condition until restored, means ettective to restore said apparatus at the entrance to each unoccupied block, and other means effective to restore said apparatus at intermediate pointsin a block provided the apparatus is not then changed substantially to its ultimate condition and the next block in advance is unoccupied.

26. In an automatic train control system, the combination with a vehicle, of automatic train control apparatus therefor including a.

permissive speed cam adapted to be connected to the wheels of the vehicle, electrically operable means for controlling the drivin connection between said cam and the wheels of the vehicle, a circuit i-ontrolling the operation of said. means, a normally closed circuit controller for governing said circuit, and means moved concurrently with said cam for opening said circuit controller after the cam has moved to a predetermined extent.

27, In an autounitictrain control system, the con' hination with a vehicle and a track the 'ei'or divided into blocks, of automatic tra in control means pa rt-ly on the vehicle and partly along the track adapted to impose restrictions on the movement 0:]? the vehicle during: its progress through a block next in the rear of an occupied block and to continue such restrictions .until restored, governing means normally effective to remove such re strietions by restoring the train control means at intermediatepoints in a block when the next block inadvance becomes unoccupied, said train, control means being aut maticallv rendered incapable of responding to said k werning means of a block after the vehicle has traveled substantially through the preceding: block under its influence, whereby a vehicle can be automatically released trom the restrictions imposed upon itby the train control means at intermediate points in a block when trallic conditions in the next blocl: in advance become safe, but cannot be so released at such intermediate points in. a block oecupiec by another vehicle.

28. In an automatic train control system, the combination wish a vehicle :nd a tracl: therefor divided nto blocks. of train con trol. m a partly on the vehicle and partly all no track a capalile oil l on and i ally decreasing; innpations u the vehicle durino its pr s through a block. and means for transmitting; to the vehicle a. controlling impulse of a distinctive character at the entrance to each bloclr when that block is not occupied, said train control. means after changing to a predetermined extent continuing in action until restored by suchdistinctive impulse. '1

29. In an automatic train control system, the combination with a vehicle and a traclr therefor diiided into blocks, of automatic train control apparatus for the vehicle ineluding a permi sire speed device and an actual speed governor. governing means "or said apparats partly on the vehicle and partly alonethe track adapted to set said apparatus into operation upon entrance of the vehicle into a bloclr next in the rear of a block occupied by ai'iother vehicle and to continue such operation until the next block ahead "formerly occupied becomes clear. and means for restoring: said apparatus to its initial condition at the entrance to each unoccupied hloclr, said train contr l apparatus axtter ha ing been in operation during the travel oi a vehicle substantially throucjh a block continuing in action until restored bv said last mentioned means at the entrance/ to an unoccupied block.

30, In an autoinr'itic train control system the combination w th a vehieleand a track therefor dividcd into blocks. of a control relay on the vehicle. a control circuit sroverninc? said relay. means For apnlving current o'lione character to said control circuit at the entrance to each hloclr when that block is not occupied, other means t applvin 51' current of anothercl aracter to said control circult at intermediate points in a block when the next block in advance is not occupied,

and means governed in accordance with the progress of the vehicle for rendering said v se ectively respon: ive to both current-i in its control circuit or only to the firi mentioned current.

31.111 an automatic train control system,

- n the weed ii lOO the combination with a vehicle and a track therefor divided into blocks, oil. train control apparatus for the vehicle adapted to regulate its movement as it travels through a block,

i said apparatus when operating continuing in apparatus for the vehicle adapted to continue in operation after its initiation until restored. impulse transmitting means for causing restoration of said apparatus, said means being distributed along each block and being effective when the next block in ad ance is not occupied. and means associated with the train control apparatus for preventing; the influencing therco'l by said impulse transmitting means of a block who the vehicle enters that block with its train control apparatus acting. 33. An automatic train control system for railroads hav ng; divided into blooms each pro *idcd with a normally closed track circuit. automatic contr l, apparatus on a vehicle adapted when set into operation to continue in operation until restored, and means partly on the vehicle and partly along the track for setting said apparatus into oporation or restoring it during the progress of tie vehicle through a block dependent uponthe presence absence of another vehicle in a blocl: ahead, said means being in etlective the vehicle passes through a block already occiu'iied even thoiiugh the next block in. advance 'thcreol iscleari 34-. An automatic train control system tor railroads having tracks divided into blocks each provioed with a normally closed track circuit, automatic spiced control apparatus on a vehicle and control means therefor l .rving a tenocncy to assun'ie an active condition and means partly on the vehicle and partly along; the track for communicating a controllin influence to the vehicle; during its pron iihlfil'iglli a block tor maintaining said apparatus inactive or restoring" it to its inacuvo condition said means associated with each block be'in governed b* the Z) I I track circuit of the block next in advance said means being; inellective when the vehicle is in a block already occupied by anstrictions oaths-speed otsaid vehicle, means partly on the vehicle and partly along the track tor setting said apparatus into o1.)eration in the rear of an occupied block, run down device arrangci'l to change gradually to an ultimate condition a circuit controller opened when said device attains its ultimate coi'idit-ion, and control means for said apparatus governed by said circuit controller.

36. An automatic train control system com 'is'ing train control ap 'iaratus on a veli cle means l along" the track "for controlling the operation ot said apparatus in accordance-with trathe condit' is ahead, and a distance measuring device .-.or governing said apparatus, said device being; also controlled by said means. 37. An automatic train control system (.Oll'lpllSliwr automatic speed controlv appachann able speed controlling means on a ve-.

hicle determining the speed at which it may run, a run-down device adapted to change in accordance with the distance traveledby the vehicle and assume an ultimate condition in a distance less than the lengthoit a block and means controlled by said run-down de vice tor governing the o 'ieration of said s1 iced controlling means 39. In a train control system tor railroads divided into blocks, a normally inactive rundown device adapted when set into operation to change gradually toan ultimate condition inaccordance with the distance traveled by 'the vehicle, said distance being' less than the length of a block, train control means having its condition changed when the rundown device attains its ultimate condition, and tral'lic controlled means partly on the vehicle and partly along the t 'ack for auton'ia cally rendering said run-down device active or inactive. i

42:0. 7 Automatic train control equi nnent for railway vehicles comprising a rundown dcvice anti-angled to change graduallytoward an ultimate condition in ace-:nrdance with the distance traveled by the vehicle speed control apparatus and control means therefor adapted to enforce v predetermined speed hunts for the vehicle.- and means whereby said amiaratus is'governcd by said iun-down I devicewhen it attains its ultimate condition,

-11. Inan automatic speed control system for railroads divided'intoblocks, speed con trol apparatus on a vehicle adapted to en;

force a normal. maximum speed l'imit and effective when set into operation to enforce partly on the vehicle and partly predetermined lowerspeed limits, a distance measuring device adaptedto change to an ultimate condition in accordance with the movement of the vehicle, a controlling circuit for said apparatus governe by said device as the latter attains its ultimate condition, and means partly on the vehicle and partly along the track for governing said apparatus and said device in accordance with traflic conditions ahead.

42. In an automatic speed control system for railroads divided into blocks, normally inactive speed control apparatus on a vehicle, anormally inactive run-down device on the vehicle governed in accordance with the movement thereof, traiiic controlled means for rendering saidapparatus and run-down device active, a normally closed circuit controller opened by said run-down device after the vehicle has traveled a predetermined distance, and a controlling circuit for said apparatus including said circuit controller.

413. In an automatic speed control system for railroads divided into blocks, speed control apparatus on a vehicle, a run-down device adapted to change to an ultimate con dition, a circuit cont-roller actuated by said device when it attains its ultimate condition, and means governed by said circuit controller for influencing the condition of said apparatus.

44. In an automatic train control system for railroads having tracks divided into blocks, automatic train control apparatus on a vehicle adapted when set into operation to continue in operation until restored, con trol means on the vehicle adapted to be influenced from the trackway, trackway means associated with each block and governed in accordance with traitic conditions in the next block in advance for cooperating with said control means on the vehicle and cause restoration of said apparatus when said next block in advance is unoccupied, and means acting after the vehicle has traveled through a given block with its train control apparatus in operation for preventing such restoration by the trackway means associated with the next block in advance of said given block.

45. In an automatic train control system for railroads having tracks divided into blocks, automatic train control apparatus on a vehicle adapted when set into operation to impose a continuing restriction on the movement of the vehicle until restored, automatic restoring means partly on the vehicle and partly on the track for restoring said apparatus during the progress of the vehicle through the first part of a blocl: when the next block in advance thereoi not occupied, and means capableot restoring said apparatus While said automatic restoring means is ineffective.

46. In an automatic train control system for railroads having tracks divided into blocks, automatic train control apparatus on a vehicle of the type which once set into operation continues in operation until restored, automatic means partly on the track and partly on the vehicle for restoring said apparatus during the progress of the vehicle through a block provided the next block in advance is not occupied, said means being ineffective in an occupied block although the neXt block in advance thereof may not be 0 cupied.

1-7. In an automatic train control s3 tom for railroads having tracks divided into blocks, automatic train control apparatus on a vehicle including normally energized de vices ha ing a tendency to assume the active condition, said apparatus when set into operation continuing in operation until restored, control means on the vehicle adapted to be influenced from the trackway for setting said apparatus into operation, a plurality of trackway devices in each block controlled in accordance with trailic conditions in the next block in advance and each ellec-tive to influence said control means on a passing vehicle to set said apparatus into operation, and automatic tratlic controlled means for restoring said apparatus.

18. In an'automatic train control system for railroads having tracks divided into blocks, automatic train control apparatus on vehicle adapted when set into operation to continue in operation until restored, and automatic means partly on the vehicle and partly onthe track and includin a plurality of track devices in each block for setting said apparatus into operation or restoring it to its initial condition dependent upon the presence or absence of another train in the next block in advance, said means being ineffective to restore said apparatus in an occupied loclc although the next block in advance thereof may not be occupied.

19. In an automatic train control system for railroads having tracks divided into bloclzs each provided with a normally closed track circuit, the length of said blocks affording braking distance for the normal run ning speed of trains therein, the combination with automatic brake control. apparatus on a vehicle acting whenever once set into operation to impose a continuing restriction upon the movement of the vehicle until said apparatus is restored, oi cooperating tracl;- w y means and car-carried means for controlling the initiation and restoration of said apparatus, said trackway means being associated with each block and responsive to the occupancy oi the next block in ad Vance, said cooperating means acting automatically to initiate operation of said apparatus on a vehicle in a block ii the nextblock in advance is then occupied, and to re storesaid apparatusautomatically in any i 'bloek only 1:5 the ren'iaining portlon oi that same block in advance of the vehicle and also all oi the nextblock in advance are unoccupied.

50. In a system of automatic train speed controlv for railroads having tracks divided into blocks each provided with anorinally closed track circuit, said system acting miton'iatically to enforce predetermined restrictions upon the speed oi a vehicle during its progress dependent upon the presence or absence of other vehicles immediately ahead, the combination of automatic brake control apparatus on a vehicle including speed responsive ineaus determining theactiial speed of the vehicle, cooperating trackway and ear-carried means for governing the operating condition oi? said -a} )paratus and determine the speed restriction to be eflective, said track-way means being associated With each block and having its controlling condition dependent upon the pres once or absence of cars in-the next block in advanceysald trackway and car-carried cooperatingnieans acting automatically to re der said apparatus on avehicle efiective in ablock Whenever the next block in advanceis occupied and thereby establish :pre-

determined restrictions upon the speed of 534! the vehicle corresponding to its position in said l)l()ClI SLl(l cooperating meansalso acting automatically ;to control said apparatus and relieve such speed restrlctlonsWhile'the vehicle is in any block only i'f'at least the remaining portion ofthatbloek aheaclof the vehicle and all of the next-block in advance are unoccupied.

ennnnns s. BUSHNEL 

